7778420066 has 8 divisors (see below), whose sum is σ = 11669863644. Its totient is φ = 3888465520.

The previous prime is 7778420033. The next prime is 7778420081. The reversal of 7778420066 is 6600248777.

It can be written as a sum of positive squares in 2 ways, for example, as 7748400625 + 30019441 = 88025^2 + 5479^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 7778420066.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 359105 + ... + 380148.

Almost surely, 2^7778420066 is an apocalyptic number.

7778420066 is a deficient number, since it is larger than the sum of its proper divisors (3891443578).

7778420066 is a wasteful number, since it uses less digits than its factorization.

7778420066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 744516.

The product of its (nonzero) digits is 790272, while the sum is 47.

The square root of 7778420066 is about 88195.3517255870. The cubic root of 7778420066 is about 1981.3618548160.

The spelling of 7778420066 in words is "seven billion, seven hundred seventy-eight million, four hundred twenty thousand, sixty-six".